The Land Vertebrates of Pemba, Zanzibar and Mafia: a Zoo‐geographical Study.

Abstract

Recent advances in the insular ornithology, with which we have been especially concerned, made it possible for US to compare for the first time approximately complete avifaunal lists for the three big East African islands, Pemba, Zanzibar, and Mafia. We were struck by the curious distributional problems thereby raised, which, in view of the relatively easy dispersal of birds, could not adequately be considered without broadening the basis of discussion to include also terrestrial animals. Since our own special study had been the birds, it is due entirely to the assistance we have received from workers at the British Museum, especially Mr. HW Parker and Mr. R. W. Hayman, that we have been able to deal with the herpetological and the mammal faunas; for such assistance we desire to record our thanks. Lists of the vertebrates of each island were provided by Voeltzkow (1923); but he attempted no comparative study, and for the present purpose check-lists have had to be compiled practically de novo. On the one hand, we found that Voeltzkow’s lists were uncritical, especially in that the early records for ‘r Zanzibar’’were evidently not sifted to exclude those which referred to the madand. Prior to about 1887 a strip along the coasts of what are now Kenya and Tanganyika Territory was more or less subject to the Sultan of Zanzibar. It was often referred to vaguely as “Zanzibar” or “Zanzibar coast,” so that there has been a constant danger of mainland specimens being attributed to the island. After reference to the original records and, wherever possible, labels and museum entries, we have on these grounds excluded from the Zanzibar list many species that were admitted by Voeltzkow. On the other hand, the collecting that has taken place since he compiled his lists has provided many additions to the faunae, especially for Mafia. A number of them, authenticated at the British Museum, have not previously been reported. No claim can be made that the fauna has been completely worked out for any one of the classes or islands.